/git-internals-presentation

A reveal.js presentation on the internals of git.

Primary LanguageJavaScriptMIT LicenseMIT

Git Internals Presentation

Part 1 Demo Instructions

  1. Make a demo directory and "cd" into it.
  • mkdir demo && cd demo
  1. Initialize git repository.
  • git init

  1. Split terminal horizontally (Ctrl + Shift + D in Hyper.js).

  2. Execute watch -d "find .git/objects -type f -printf \"%Tr %p\n\"| sort -n | cat --number" in 2nd terminal to the right.

    • If the watch command is unavailable, here's a custom bash script which can serve the same purpose:
    #!/bin/bash
# https://gist.github.com/espaciomore/    28e24ce4f91177c0964f4f67bb5c5fda
# https://gist.github.com/gbroques/    6ab813236b5e7490b552465196afd5d7
ARGS="${@}"
clear; 
while(true); do 
OUTPUT=$(find .git/objects -type f -printf "%T@   %Tr   %p\n" | sort -n | awk '{print $2 " " $3 " "   $4}' |   cat --number)
clear
printf "\n"
echo -e "${OUTPUT[@]}"
sleep 2
done

  3. Make a file 1.txt with "one text" content.

  • echo "one text" > 1.txt
  1. Add 1.txt to the staging area.
  • g add .
  1. Show echo "one text" | git hash-object --stdin
  2. Make an "Initial commit".
  • git commit -m "Initial commit"
  1. Make a change to 1.txt
  • echo "a change" >> 1.txt
  1. Make a 2nd commit.
  • git add . && git commit -m "Second commit".
  1. Create a new 2.txt inside a directory dir/, then make a 3rd commit:
    1. mkdir dir
    2. echo "two text" > dir/2.txt . git add . && git commit -m "Third commit"

Part 2 Demo Instructions

watch git HEAD bash script:

#!/bin/bash
# https://gist.github.com/espaciomore/28e24ce4f91177c0964f4f67bb5c5fda
# https://gist.github.com/gbroques/109615d7304bfea189c09c2709d77e96
ARGS="${@}"
clear; 
while(true); do 
  OUTPUT=$(cat .git/HEAD)
  ref=$(echo $OUTPUT | awk '{print $2}' | xargs -I {} cat .git/{})
  commit_message=$(git log --format=%B -n 1 $ref)
  clear
  printf "\n    HEAD\n"
  echo -e "        ${OUTPUT[@]}"
  printf "\n    ref:\n"
  echo -e "        ${ref}"
  printf "\n"
  echo -e "        ${commit_message}"
  sleep 2
done

Generating Slides

Navigate to:

http://localhost:8000/?print-pdf

Ctrl + P to print and save.

Alternatively decktape, but this doesn't render images well:

decktape http://localhost:8000/ slides.pdf